More and more people are adopting a plant-based or vegetarian diet to improve their health1. There is significant evidence that a plant-based diet leads to lower risk of obesity, chronic diseases, and some cancers2,3. But do vegetarians live longer?
Most studies conclude that vegetarians do not live longer than meat-eaters. However, this conclusion is not as straightforward as it seems.
First, let’s look at the evidence that there are no longevity benefits to a vegetarian diet. A 2016 study4 from the U.K. found mortality rates among vegetarians and non-vegetarians to be comparable. A 2017 study5 from Australia had the same result. And a 2017 meta-analysis6, or study of studies, reviewed 96 other studies and found that, while vegetarian diets conferred many protective health benefits, all-cause mortality was the same as for meat-eaters.
Longevity Study Drawbacks and Considerations
There are important considerations to take into account with these studies:
- Vegetarians are not necessarily healthy eaters. While they don’t eat meat, it’s possible that some may eat a lot of junk food, which could, in effect, cancel out the presumed benefits of not eating meat.
- The modern medical system may be “propping up” mortality among people with unhealthy diets. Now that there are surgeries and/or medicines for heart disease, high blood pressure, diabetes, cancer, and so on, people who may have had a shorter life are able to stick around longer.
- Even among the studies that show similar levels of mortality for different diets, vegetarians may enjoy a better quality of life throughout their lives, with lower incidences of chronic diseases like heart disease and diabetes.
Overall Healthfulness of Diet Matters Most
A 2019 study7 sought to understand mortality rates for healthful diets, not just vegetarian diets. They created a score called hPDI for a healthier plant-based diet, and a score for uPDI, for an unhealthy plant-based diet. They assigned each study subject a score at baseline, and then tracked their eating habits over time. They found that, even though all study subjects ate a plant-based diet, people with the healthiest overall diets were the healthiest themselves, and lived longer.
The authors state:
“Improving plant-based diet quality over a 12-year period was associated with a lower risk of total and CVD (cardiovascular disease) mortality, whereas increased consumption of an unhealthful plant-based diet was associated with a higher risk of total and CVD mortality.”
Two other studies using the hPDI and uPDI, and included meat-eaters, scores saw similar results. Researchers from John Hopkins8 found that plant-based diets that were above average in overall healthfulness were associated with a lower risk of all-cause mortality in US adults.
Another study9 that included almost 117,000 people found:
“Higher intake of a plant-based diet index rich in healthier plant foods is associated with substantially lower CHD (chronic heart disease) risk, while a plant-based diet index that emphasizes less-healthy plant foods is associated with higher CHD risk.”
Definition of an Overall Healthy Diet
You may be wondering how overall healthy and unhealthy diets are defined, aside from being plant-based. In the study just mentioned, the authors defined healthy and unhealthy foods as follows:
Healthy: whole grains, fruits/vegetables, nuts/legumes, oils, tea/coffee
Unhealthy: juices/sweetened beverages, refined grains, potatoes/fries, sweets
Authors of a frequently-cited study10 on Seventh Day Adventists (most of whom are vegetarians), found that vegetarian diets were associated with lower mortality (i.e. longer life) from all causes, and with some reductions in specific-cause mortality. These favorable results for vegetarians were more pronounced in men than in women.
This same study collected all diet factors from a range of previous studies that are associated with decreased mortality (longer life):
- Fruits
- Cereal fiber
- Polyunsaturated fatty acids (PUFAs)
- Green salad
- Mediterranean diet
- “Healthy” or “prudent” diet
- Plant-based diet
- Plant-based low carbohydrate diet
- Vegetarian diet
They also summarized diet factors associated with increased mortality (shorter life):
- High-glycemic load
- Meat
- Red meat
- Processed meat
- Potatoes*
- Increased energy intake
- Annimal-based low carbohydrate diet
*The study says the method of preparation was not taken into account; so the results could be because the potatoes were fried; preparation and serving methods were not disclosed11. Other studies12,13 show no association between potato consumption and mortality. (whew! I love baked potatoes with broccoli and vegan plain yogurt).
Better Quality of Life for Vegetarians
The same meta-analysis6 mentioned above reports that there is “a significant protective effect of a vegetarian diet versus the incidence and/or mortality from ischemic heart disease (-25%) and incidence from total cancer (-8%). Vegan diet conferred a significant reduced risk (-15%) of incidence from total cancer.”
Another meta-analysis14 looked at six studies which included almost 125,000 people from UK, Germany, USA, the Netherlands, and Japan, and found similar results (all-cause mortality was not studied):
“Our results suggest that vegetarians have a significantly lower ischemic heart disease mortality (29%) and overall cancer incidence (18%) than nonvegetarians.”
If you and I both live to age 90, and I am disease-free, and you are overweight, taking medications and possibly being treated for heart disease or cancer, I am going to enjoy those 90 years more than. you are. It’s not just about mortality age, in my book.
Summary
While more research is needed, there is substantial evidence that eating a plant-based diet, as part of an overall healthy diet (not combining it with junk food) can lead to a longer life. And minimizing animal foods can lead to reduced obesity, chronic disease, and some cancers, which will make for a healthier, more enjoyable life. Also consider the benefits of fewer trips to the doctor; reduced medical costs; and less of a burden on the environment.
For me, the weight of evidence is clearly in favor of eating a vegetarian/plant-based diet. If you read this far, thank you! I hope you found it helpful!
Is it expensive to be a vegan? Get a cost analysis here.
One key to healthy eating is salad. Read here to learn about the healthiest type of salad green.
What’s the healthiest apple variety? Find out here.
Resources
1 https://www.ipsos-retailperformance.com/en/vegan-trends/.
2 Le LT, Sabaté J. Beyond meatless, the health effects of vegan diets: findings from the Adventist cohorts. Nutrients. 2014;6(6):2131-2147. Published 2014 May 27. doi:10.3390/nu6062131.
3 Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016;116(12):1970-1980. doi:10.1016/j.jand.2016.09.025.
4 Appleby PN, Crowe FL, Bradbury KE, Travis RC, Key TJ. Mortality in vegetarians and comparable nonvegetarians in the United Kingdom. Am J Clin Nutr. 2016;103(1):218-230. doi:10.3945/ajcn.115.119461.
5 Mihrshahi S, Ding D, Gale J, Allman-Farinelli M, Banks E, Bauman AE. Vegetarian diet and all-cause mortality: Evidence from a large population-based Australian cohort – the 45 and Up Study. Prev Med. 2017;97:1-7. doi:10.1016/j.ypmed.2016.12.044.
6 Dinu M, Abbate R, Gensini GF, Casini A, Sofi F. Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies. Crit Rev Food Sci Nutr. 2017;57(17):3640-3649. doi:10.1080/10408398.2016.1138447.
7 Baden MY, Liu G, Satija A, et al. Changes in Plant-Based Diet Quality and Total and Cause-Specific Mortality. Circulation. 2019;140(12):979-991. doi:10.1161/CIRCULATIONAHA.119.041014.
8 Kim H, Caulfield LE, Rebholz CM. Healthy Plant-Based Diets Are Associated with Lower Risk of All-Cause Mortality in US Adults. J Nutr. 2018;148(4):624-631. doi:10.1093/jn/nxy019.
9 Satija A, Bhupathiraju SN, Spiegelman D, et al. Healthful and Unhealthful Plant-Based Diets and the Risk of Coronary Heart Disease in U.S. Adults. J Am Coll Cardiol. 2017;70(4):411-422. doi:10.1016/j.jacc.2017.05.047.
10 Orlich MJ, Singh PN, Sabaté J, et al. Vegetarian dietary patterns and mortality in Adventist Health Study 2. JAMA Intern Med. 2013;173(13):1230-1238. doi:10.1001/jamainternmed.2013.6473.
11 González S, Huerta JM, Fernández S, Patterson AM, Lasheras C. Differences in overall mortality in the elderly may be explained by diet. Gerontology. 2008;54(4):232-237. doi:10.1159/000135069.
12 Darooghegi Mofrad M, Milajerdi A, Sheikhi A, Azadbakht L. Potato consumption and risk of all cause, cancer and cardiovascular mortality: a systematic review and dose-response meta-analysis of prospective cohort studies. Crit Rev Food Sci Nutr. 2020;60(7):1063-1076. doi:10.1080/10408398.2018.1557102.
13 Moholdt T, Nilsen TIL. Frequency of Boiled Potato Consumption and All-Cause and Cardiovascular Disease Mortality in the Prospective Population-Based HUNT Study. Front Nutr. 2021;8:681365. Published 2021 Jul 19. doi:10.3389/fnut.2021.681365.
14 Huang T, Yang B, Zheng J, Li G, Wahlqvist ML, Li D. Cardiovascular disease mortality and cancer incidence in vegetarians: a meta-analysis and systematic review. Ann Nutr Metab. 2012;60(4):233-240. doi:10.1159/000337301.
